Treating Soybeans with New Herbicide Traits

Mark VanGessel, Extension Weed Specialist;

A recent article in an ag newsletter raised the question of what herbicide brands can be sprayed on the new herbicide traits. The article asked about use of glyphosate on soybean varieties that are “glyphosate-resistant” but the soybeans are not designated as “Roundup Ready”. Many brands of glyphosate are labeled specifically for “Roundup Ready” crops. So with the help of industry contacts and Delaware Department of Agriculture we have sorted out the issues. It is important that crops are treated only with the registered herbicide brands, so it may require re-reading labels to be sure they can be applied to new varieties.

Liberty Link crops are stated on the label of most brands of glufosinate, the active ingredient in Liberty.

Roundup Ready crops are stated on most brands of glyphosate.

Roundup Ready 2 Xtend soybeans can be treated with most glyphosate brands because of the “Roundup Ready” designation. But these can only be treated with dicamba formulations approved for “Xtend”-branded crops (Engenia, Fexapan, or Xtend).

Enlist E3 soybeans are resistant to glyphosate, glufosinate, and 2,4-D choline. Enlist One (2,4-D choline alone) and Enlist Duo (2,4-D choline plus glyphosate) can be applied to these soybeans. But Enlist soybeans do not carry the brand name of “Roundup Ready” or “Liberty Link”. If the glyphosate brand says only use on “Roundup Ready” crops then is cannot be applied to Enlist soybeans. These soybeans can only be treated with glyphosate brands that allow application to “glyphosate-resistant” or “glyphosate-tolerant” crops. Likewise, if the label specifies use on “Liberty-Link” soybeans then it cannot be used. Only glufosinate brands that say they can be applied to “glufosinate-resistant” or “glufosinate-tolerant” crops are allowed.

Enlist corn is resistant to 2,4-D choline, glyphosate and registered postemergence grass herbicides. Currently, Assure II (quizalofop) has a special label for use with Enlist corn.

LLGT27 Soybeans are resistant to glyphosate, glufosinate, and an HPPD herbicide. These soybeans are branded as “Liberty Link” and can be treated with most glufosinate brands. While these soybeans are resistant to glyphosate they are not “Roundup Ready” and must be treated only with glyphosate brands labeled for “glyphosate-resistant” or “glyphosate-tolerant” soybeans. The HPPD herbicide product currently is not approved by the EPA.

Many herbicide companies are changing their labels to allow application to these new soybeans, so more brand options will soon be available. But be sure to read the label of the brand you intend to use to be sure it is labeled for use.

If using crops with herbicide-tolerance traits be sure you keep detailed records of which fields are planted with which traits. Likewise, when switching varieties, you may need to clean out your planter to avoid mixing traits.